• Patient is an adult male/female ≥ 18 years old at the time of informed consent and has signed informed consent before any trial related activities and according to local guidelines. Female patients must be postmenopausal. • Patient has a histologically and/or cytologically confirmed diagnosis of estrogen-receptor positive and/or progesterone receptor positive breast cancer by local laboratory and has HER2-negative breast cancer. • Patient must have either measurable disease by RECIST 1.1 or at least one predominantly lytic bone lesion. • Patient has advanced (loco regionally recurrent not amenable to curative therapy, e.g. surgery and/or radiotherapy, or metastatic) breast cancer. Patients may be: - newly diagnosed advanced/metastatic breast cancer, treatment naïve - relapsed with documented evidence of relapse more than 12 months from completion of (neo)adjuvant endocrine therapy with no treatment for advanced/metastatic disease - relapsed with documented evidence of relapse on or within 12 months from completion of (neo)adjuvant endocrine therapy with no treatment for advanced/metastatic disease - relapsed with documented evidence of relapse more than 12 months from completion of adjuvant endocrine therapy and then subsequently progressed with documented evidence of progression after one line of endocrine therapy (with either an antiestrogen or an aromatase inhibitor) for advanced/metastatic disease - newly diagnosed advanced/metastatic breast cancer at diagnosis that progressed with documented evidence of progression after one line of endocrine therapy (with either an antiestrogen or an aromatase inhibitor) • Patient has an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 • Patient has adequate bone marrow and organ function Other Protocol-defined Inclusion/Exclusion may apply.